Shale distillation with fluidized residue treatment



March 13, 1951 H. v. ATwr-:LL

SHALE DISTILLATION WITH FLUIDIZED RESIDUE TREATMENT Filed May 29; 1946 Patented Mar. 13, v1951 ,z -1

UNITED iii ortica SHALE DISTELLATEON VIII-H FLUIDIZED RESDUE TREATMENT Haroldv V. Atweil, Beacon, N. Y., assignor to The Texas Company, New'iork, N. Y., a corporation of Belaware Application May '29, 194e,v serial 10.673,141

e claims. (ci. aca-.15)

This invention relates to the distillation of oil shales for the recovery of volatilizable constituents therefrom.

In accordance with the invention a solid, com'- s minuted or powdered material is heated to a high temperature by being contacted with combustion gases, the highly heated comminuted or powderezl materialis brought into contact with, and iiuidized in, a gaseous medium to obtain heat transfer to the gaseous medium and the heated gaseors medium is directed into contact with the shale to effect the distillation thereof. `1

In the distillation'of oil shale more or less disintegration takes place so as to produce quantii ties of pulverulent or comminuted material and in accordance with the invention this pulverized or comminuted material mayA be removed from the distilling zone before complete removal of its hydrocarbon or carbonaceous content and this material is fluidized and subjected to combusion to thereby impart a high degree of heat to the material. The heated material is then iiuidiaed with gas, preferably a hydrocarbon gas, and the resultant heated gas is delivered to the retort to effect destructive distillation of the shale.

The accompanying drawing is a ow diagram illustrating a preferred embodiment of the invention.

Referring to the drawing, comminuted or powdered solid material is contained in a hopper or feeding means itl. This comminuted material preferably includes finely divided or powdered shale recovered froml the distillation of 'the raw shale and which contains some hydro Vcarbon or lcarbonaceous content not removed'in f the distillation. Makeup comminuted material from an extraneous source may be included in the material contained in the hopper. A fiuidiz- Aing medium is directed through line lland serves, to withdraw comminuted material from" the lhop-per I@ and fluidize it. The uid-izingme- Vdium may be air or oxygen-containing gas vor inert gas. Preferably fuel gas such as recycle gas recovered in the process is used as the iiuidizing medium. The comminuted material is trans- "4 ported in suspension in the fluid medium through line i l thencethrough lines i2 and i3A toa cornbustion'chamber It. When air or oxygen-cona taining gas is not used as the fluidizing medium, p which will generally be the casein order to avoid combustion in the transporting lines, air or oxygen-containing gas is introduced directlyto the combustion chamber through line IZA. In the combustion chamber the carbonaceous material contained on-the comminuted solid-material is burned under iiuidized conditions. In cases where the quantity of carbonaceous material on the spent shale and the quantity of fuel gas Used in fluidizing and transporting the comminuted solid material is insuncient to obtain the extent of combustion desired, auxiliary fuel gas may be introduced through a line l5.

The upper portion of the combustion chamber i5 may be of increased diameter to provide a separating zone MA for separating the combustion gases from the powdered material. The separated gases flow out throughv alfine I. Cyclone separators may be used in lieu of the separating zone-MA, or in addition thereto,- to assure complete separation. l

*The comminutedmaterial collects in a scc- `tion i? shielded from the flow of gases. The maeri'al-is withdrawn through a standpipe la-to which may be connected one or more pipes such lwherein theA comminuted material and the gaseous medium are in contact under fluidized con.- ditions. The comminuted rmaterial and gaseous medium are maintained in a dense phase and in a turbulent condition in the lower sections of the chamber l which conditions are conductive to maximum'transfer of heat from the comm-inuted material to the gas. Theupper portion foif the-chamberl 2'! maybe of increased diameter tol provide a separating zone 22 for separating the comminuted material from the gas.

The comminuted material collects in a section 23 shieided from the flow of gases and is Withdrawnthrough a standpipe 2t to which maybe `connected one or more pipes suchas 25 for introducing small quantities of gasto maintain the material in the standpipe inan' aerated condition, A'iiuidizing gas, such'a's air or recycle 'hy'- chocar-bon gas, introduced through line zfu'nc'- tions'to'withdraw the comminuted material from the standpipe 2li and recycle it to the combustion chamber is. When itis not desired to re'- -cycle thev-con-irninuted material it is withdrawn through a line 26. In some cases only a portion of the comminuted material is recycled and the excess is withdrawn through the line 26.

The separated gas is withdrawn from the separating section 22 of the chamber 2| through a line 2 and is delivered to a distilling retort 28 for distilling the shale. Lump shale is charged through a screw conveyor 29 to the upper end of the retort 2S. The hot gaseous medium is preferably introduced to the lower portion of the retort 28 as shown so as to thus provide countercurrent contacting of the hot gas with the lump shale. The volatilized products are removed through a vapor line 3| and conducted to Suitable fractionating equipment (not shown) to recover the desired products.

The shale from which substantially all or at least the bulk of the volatilizable material has been distilled off is Withdrawn through the bottom of the retort and may be removed by means of a screw conveyor 30.

The removal of the volatilizable constituents or the greater portion thereof from the lump shale will normally effect more or less disintegration of the lumps so that portions of the niaterial discharged from the retort will be in a sufficiently comminuted form to be fluidized with a gaseous or vaporous medium. In such-cases this comminuted material, after screening when necessary, may be directed to the hopper li) for fluidizing in the line ll and deliveryr to the combustion chamber i4. Fragments that are too large for fluidizing may be discarded cr they may readily be ground to a proper size since the residual product from the distillation is normally in a friable condition and much more easily pulverized than the raw shale before distillation. Frequently a certain amount of shale dust will pass out from the retort through the vapor line and by inserting a cyclone separator in the line the dust may be separated and directed to the hopper l0.

Oil shales vary considerably in characteristics` but generally speaking hydrocarbon gases are evolved at initial temperatures around G50-750 F., oil vapors and gases are freely given off at temperatures around the 900 F. level and as a rule all the recoverable vapors will be removed at a temperature approximating 100()o F. or at somewhat lower temperatures. begins to come olf at about 555 F. and may continue more or less through the distillation. In practicing the invention the fiuidized comminuted material is subjected to combustion temperatures of about 2000 to 2500 F. in the combustion zone. The temperature of combustion should be kept below the melting point of the ash or solid material. The highly heated comrninuted material upon being iluidized with the gaseous medium, preferably recycle hydrocarbon gases, imparts heat to the gaseous medium which is then delivered to the shale retort at temperatures approximating 1500 F. With the entering gas at this temperature an effective distilling zone at temperatures of about 90B-1000u F. is maintained in the lower sections of the retort to thereby effect destructive distillation of the shale. rThe evolved vapors and gases are subjected to fractionation to recover the hydrocarbon oils and gases. When recycling hydrocarbon gas the gas Yis advantageously preheated in an exchanger receiving heat from the combustion gases leaving the combustion chamber prior to being used to fluidize the hot comminuted material which is Awithdrawn from the combustion chamber. It is advantageous to withdraw the residual shale from Ammonia gas the retort before complete volatilization of carbonaceous material so that a certain amount of the carbonaceous or hydrocarbon content of the shale may remain with the withdrawn residual shale. The combustion of this carbonaceous or hydrocarbon material in the combustion zone serves to provide the necessary heat for heating the comminuted solid material therein. Fuel gas introduced into the combustion chamber, preferably recycle gas, provides such additional heating as may be required.

Although a preferred embodiment of the invention has been described herein, it will be understood that Various changes and modifications may be made therein, while securing to a greater or less extent some or all of the benefits of the invention, without departing from the spirit and scope thereof.

I claim:

l. The method of distilling oil shales that comprises charging lump shale to a distilling zone, introducing gas heated as hereinafter specified to the distilling zone to effect destructive distillation of the shale and produce resultant disintegration thereof with formation of comminuted residual shale, withdrawing comminuted residual shale containing carbonaceous material from the distilling zone and iiuidizing it in a fluidizing medium, transporting the comminuted residual shale in suspension in the fiuidizing medium to a combustion zone, subjecting the uidized comminuted residual shale therein to combustion under iluidized conditions, separately withdrawing resultant highly heated comminuted burned shale from the combustion zone, fluidizing it with gas and passing the nuidized stream into a zone wherein the gas and comminuted shale are in Contact in dense phase and turbulent conditions to effect rapid transfer of heat from the shale particles to the gas, separately withdrawing resultant heated gases and comminuted material from said zone and introducing the separated gas into the distilling zone to effect the destructive distillation of the lump shale as aforesaid.

2. The method of distilling oil shales that comprises charging lump shale to a distilling zone, introducing gas heated as hereinafter specified to the distilling zone to effect destructive distillation of the shale and produce resultant disintegration thereof with formation of comminuted residual shale, withdrawing residual shale containing carbonaceous material from the distilling zone, obtaining comminuted residual shale from the residual shale so withdrawn and uidizing it in a fluidizing medium, transporting the comminuted residual shale in suspension in the fiuidizing medium to a combustion zone, subjecting the fluidized comminuted residual shale therein to combustion under uidized conditions, separately withdrawing resultant highly heated comminuted burned shale from the combustion zone, fluidizing it with gas and passing the iiuiclized stream into a zone wherein the gas and comminuted shale are in contact in dense phase and turbulent conditions 'to effect rapid transfer of heat from the shale particles to the gas, separately withdrawing resultant heated gases and comminuted material from said zone and introducing the separated gas into the distilling Zone to effect the destructive distillation of the lump shale as aforesaid.

3. The method of distilling oil shales that comprises charging lump shale to a distilling zone, introducing gas heated as hereinafter specied 5 to the distilling zone to effect destructive distillation of the shale and produce resultant disintegration thereof with formation of comminuted residual shale, withdrawing residual shale containing carbonaceous material from the distilling zone, separating comminuted residual shale from the residual shale so withdrawn and uidizing it in a fluidizing medium, transporting the comminuted residual shale in suspension in the iiuidizing medium to a combustion zone, subjecting the fluidized comminuted residual shale therein to combustion under uidized conditions, separately withdrawing resultant highly heated comminuted burned shale from the combustion zone, iiuidizing it with gas and passing the uidized stream into a zone wherein the gas and comminuted shale are in contact in dense phase and turbulent conditions to eiect rapid transfer of heat from the shale particles to the gas, separately withdrawing resultant heated gases and comminuted material from said zone and introducing the separated gas into the distilling zone to eiect the destructive distillation of the lump shale as aforesaid.

HAROLD V. ATWELL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

1. THE METHOD OF DISTILLING OIL SHALES THAT COMPRISES CHARGING LUMP SHALE TO A DISTILLING ZONE, INTRODUCING GAS HEATED AS HEREINAFTER SPECIFIED TO THE DISTILLING ZONE TO EFFECT DESTRUCTIVE DISTILLATION OF THE SHALE AND PRODUCT RESULTANT DISINTEGRATION THEREOF WHICH FORMATION OF COMMINUTED RESIDUE SHALE, WITHDRAWING COMMINUTED RESIDUAL SHALE CONTAINING CARBONACEOUS MATERIAL FROM THE DISTILLING ZONE AND FLUIDIZING IT IN A FLUIDIZING MEDIUM, TRASPORTING THE COMMUNITED RESIDUAL SHALE IN SUSPENSION IN THE FLUIDIZING MEDIUM TO A COMBUSTION ZONE, SUBJECTING THE FLUIDIZED COMMINUTED RESIDUAL SHALE THEREIN TO COMBUSTION UNDER FLUIDIZED CONDITIONS, SEPARATELY WITHDRAWING RESULTANT HIGHLY HEATED COMMINUTED BURNED SHALE FROM THE COMBUSTION ZONE, FLUIDIZING IT WITH GAS AND PASSING THE FLUIDIZED STREAM INTO A ZONE WHEREIN THE GAS AND COMMINUTED SHALE ARE IN CONTACT IN DENSE PHASE AND 